I have an r61 ordered with a t8100 penryn CPU and x3100 integrated graphics. I will be running primarily 32 bit OS to start, at least until there is wider 64 bit support. I selected a single 1 gb so-dimm for memory and I now looking to order more ram, but I have a few questions.

I understand that with a 32 bit OS there is a 4 gig limit to addressable ram, including all the ram on every board, drive and gpu. I have read some things that make me think that the santa rosa chipset is limited to 3 gig period, not what ever is left after subtracting all the caches found through out a pc, is this true? If not then going with 2x2gb would free up a little ram, considering the ram the GPU steals over only having 3 gb.

Is there really any advantage to matched 2 gb dimms vs 1 1 gb and 1 2 gb dimm for dual channel. I understand that on early systems with DC ram often unmatched ram would cause issues, but now?

I am guessing that you are running Vista correct? Regardless, your chipset can handle much more than 3Gb but yes, any 32MB OS is limited in how much RAM is recognized. My guess is that if you installed two 2GB sticks your 32bit OS would only recognize about 3.2GB of it but hat doesn't mean that the remaining 800MB would not be used. It gets complicated but paging operations and other housekeeping will make some use of the "unseen" memory. Remember your 3100 IG chip utilizes system memory.

Now, by installing a 2GB stick alongside the 1GB stick you will lose Dual Channel Capability. That isn't good as it will have an impact on performance and depending on what program you are running it could be substantial. Also, with the incredibly low prices on DDR2 memory right now, it is not worth the savings.

If money is an issue I would get another stick of 1GB RAM that closely matches what you have installed. My guess is that a 1GB stick of Corsair DDR2-667 will work in dual channel mode with your present stick of RAM. If you want to make sure what your RAM is running at, download CPUz at http://www.cpuid.com and look under memory to see what speeds and timings you are getting.

Personally I would take advantage of the low memory prices at this time and install two, 2GB sticks now and not worry about finding yourself short of memory later. You can get a full 4GB (2x2GB) of matched Corsair DDR2-667 RAM for $74.99 with free shipping and it is guaranteed for life.http://www.newegg.com/Product/Product.a ... 6820145193

In a year it could cost twice as much or more. Install takes about 5-10 minutes with a small Phillips head screwdriver.

Shack80 wrote:Thanks for the info! 2x2gb it is. I was thinking that was the way to go, but having done a lot of research before buying a laptop my head is spinning and needed clarification. Thanks.

i saw a spec somewhere in my travels (if i remember where, i'll repost) that said max system RAM = 3GB. that was for my system - see specs in my sig.

i would've gone the 2x2GB route too if i didn't see this. also i have desktop experience in which XP did not want to see anymore than 3GB due to the BIOS. the machine ran significantly slower with 4GB. so in the interest of avoiding another nightmare, i ordered 2x1GB instead. just my $.02 and of course YMMV.

Any 32bit OS will be limited in seeing more than about 3GB of RAM. Usually you'll see 3.2Gb or so. That doesn't mean that chunks isn;'t being addressed and used. It has nothing to do with BIOS with the latest chipsets, it is strictly a function of the OS at system handoff from BIOS to OS.

Some of the older AMD CPU's had a huge problem addressing more than two dual sided sticks of RAM. This was a function of the onboard memory processing. It has since been fixed and in fact Intel will be going to onboard memory processing with Nehalem. The NB as we know it will become a glorified SB chip in the very near future and the SB will most likely disappear fairly quickly since a NB chip without a memory controller, and on a 45nm architecture, will easily be able to handle all system functions.